The purpose of a damping device in a percussion device in a rock drilling machine is to protect the machine from reflected shock waves occurring during drilling. The damping device also has the purpose of providing better conditions for transferring the feed force from a rock drill rig over the drill steel to the rock by ensuring rock contact during drilling.
A previously known so called floating damping device for percussive devices includes a first chamber which is connected to an accumulator and a second chamber in order to cushion reflexes emanating from the drill steel. A damping piston snuggly fits into the second chamber which results in that reflexes from the rock are cushioned in that liquid is pressed out through the slot formed between the piston and the machine housing when the piston moves in a direction opposite to the striking direction.
For the purpose of obtaining a so called floating position, around which it can be moved in the striking direction as well as opposite thereto, and in which the damping piston is intended to be positioned prior to a strike, the damper is supplied with a constant damper liquid flow.
It is aim of the present invention to provide a further development of previously known damping devices which generally seen addresses certain problems of the existing technology.